Passage V

Extremophiles: Amazing Microbial Survivors

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Some live in airless seams of burning rock; miles beneath Earth's surface and around the hydrothermal vents of deep-sea volcanoes. Others, salt-encrusted, "sleep" in ancientcaverns, waking after centuries to feed andto be bred. Radioactive pools of toxic wasteare okay for others to live in; even acid cannot kill them. In lightless vacuums and locals once thoughtto hot, to cold or to poisonous, to sustain life, there exists a wealth of microbial organisms. These single-called survivors called extremophiles, don't merely endure environments too severe for other life forms; they thrive in them.

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Heat-loving extremophiles, or thermophiles, flourished in temperatures over 150 degrees Celsius. Scientists have collected them from the Yellowstone National Park’s thermal pools, the park abounding with geysers like Old Faithful, and from radioactive rock deep within South African gold mines.

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In the hot waters surrounding Juan de Fuca Ridge in the Pacific Ocean, thermophiles ensure the survival of other marine life. (70) Here, the ocean floor is scarred by earthquakes and underwater volcanoes. Poisonous waters from cracks at temperatures up to 360 degrees Celsius gush in the ocean floor, and thermophiles convert the toxic chemicals into food for crabs, giant worms, and other deep-sea life.

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Psychrophiles live in harsh and inhospitable places on our planet. One ancient breed of psychrophile lives in million-year-old ice miles below an Antarctic glacier. In the ice of the South Pole, psychrophiles survive not only darkness and subzero temperatures but also ultraviolet radiation.

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If life can persist in extreme environments on Earth, scientists speculate that life may endure under similar conditions elsewhere, perhaps in the frozen seas or the exploding volcanoes of Jupiter’s moons, or beneath the barren landscape of Mars. (74) Nevertheless, findings suggest that life—at least on the microbial level—may flourish throughout the universe in places we have yet to look.